Implement exit statuses

[ream88]

Thanks for merging 92b48e4, however I just found another small thing we could improve. Currently the mix tasks included in hex do all exit with code 0, even when an error occurred. This PR changes this to 1 which helps with scripts for example on GitHub CI.

[wojtekmach]

we have a set_exit_code utility function:

% rg set_exit_code
lib/mix/tasks/hex.repo.ex
230:        Mix.Tasks.Hex.set_exit_code(1)
235:        Mix.Tasks.Hex.set_exit_code(1)

lib/mix/tasks/hex.ex
420:    def set_exit_code(code), do: throw({:exit_code, code})
423:    def set_exit_code(code), do: System.at_exit(fn _ -> System.halt(code) end)

lib/mix/tasks/hex.publish.ex
104:              _ -> Mix.Tasks.Hex.set_exit_code(1)
157:            Mix.Tasks.Hex.set_exit_code(1)

lib/mix/tasks/hex.audit.ex
42:        Mix.Tasks.Hex.set_exit_code(1)

lib/mix/tasks/hex.info.ex
80:        Mix.Tasks.Hex.set_exit_code(1)
85:        Mix.Tasks.Hex.set_exit_code(1)
98:        Mix.Tasks.Hex.set_exit_code(1)
103:        Mix.Tasks.Hex.set_exit_code(1)

lib/mix/tasks/hex.outdated.ex
130:    if outdated?, do: Mix.Tasks.Hex.set_exit_code(1)
196:          Mix.Tasks.Hex.set_exit_code(1)
202:          Mix.Tasks.Hex.set_exit_code(1)

lib/mix/tasks/hex.package.ex
253:      Mix.Tasks.Hex.set_exit_code(code)
266:      Mix.Tasks.Hex.set_exit_code(code)

if it's not used on the task you worked on, could you send another PR using that utility? Thanks!

[ream88]

Ah sorry, I did not check the other tasks. Yep will create a new PR.